Tetracyclic 1,2-dihydroquinolines of structure 7 are key intermediates in the preparation of a number of steroid receptor modulating compounds {see for example: "Preparation of Quinolines and Fused Quinolines as Steroid Receptor Modulators", T. K. Jones, M. E. Goldman, C. L. F. Pooley, D. T. Winn, J. P. Edwards, S. J. West, C. M. Tegley, L. Zhi, L. G. Hamanm, R. L. Davis, L. J. Farmer, PCT Int. Appl. Pub. No. WO 96/19458; "Steroid Receptor Modulator Compounds and Methods", T. K. Jones, C. M. Tegley, L. Zhi, J. P. Edwards, S. J. West, U.S. Pat. No. 5,693,646; "Steroid Receptor Modulator Compounds and Methods", T. K. Jones, L. Zhi, 3. P. Edwards, C. M. Tegley, S. J. West, U.S. Pat. No. 5,696,127), and are prepared by a multi-step route culminating in the treatment of an aniline of structure 5 with a ketone and iodine at elevated temperatures in a process known as the Skraup reaction {see: "The Skraup Synthesis of Quinolines", R. H. F. Manske and M. Kulka, Organic Reactions, 7 (1953) 59-98; "2,4-Dimethylquinoline", W. R. Vaughan, Org. Synth. Coll. Vol III, (1955) 329-332}: ##STR1##
Many 1,2-dihydroquinolines of structure 7 are themselves steroid receptor modulating compounds. (See for example: "Preparation of Quinolines and Fused Quinolines as Steroid Receptor Modulators", T. K. Jones, M. E. Goldman, C. L. F. Pooley, D. T. Winn, J. P. Edwards, S. J. West, C. M. Tegley, L. Zhi, L. G. Hamann, R. L. Davis, L. J. Farmer, PCT Int. Appl. Pub. No. WO 96/19458; "Steroid Receptor Modulator Compounds and Methods", T. K. Jones, L. Zhi, C. M. Tegley, D. T. Winn, L. G. Hamann, J. P. Edwards, S. J. West, U.S. Pat. No. 5,693,647. } Other 2,2-disubstituted 1,2-dihydroquinolines are also modulators of steroid receptors. (See for example: "Preparation of Quinolines and Fused Quinolines as Steroid Receptor Modulators", T. K. Jones, M. E. Goldman, C. L. F. Pooley, D. T. Winn, J. P. Edwards, S. J. West, C. M. Tegley, L. Zhi, L. G. Hamann, R. L. Davis, L. J. Farmer, PCT Int. Appl. Pub. No. WO 96/19458; "Steroid Receptor Modulator Compounds and Methods", T. K. Jones, D. T. Winn, L. Zhi, L. G. Hamann, C. M. Tegley, C. L. F. Pooley, U.S. Pat. No. 5,688,808; "Steroid Receptor Modulator Compounds and Methods", T. K. Jones, M. E. Goldman, C. L. F. Pooley, D. T. Winn, J. P. Edwards, S. J. West, C. M. Tegley, L. Zhi, U.S. Pat. No. 5,688,810; "Steroid Receptor Modulator Compounds and Methods", T. K. Jones, D. T. Winn, M. E. Goldman, L. G. Hamann, L. Zhi, L. J. Farmer, R. L. Davis, U.S. Pat. No. 5,696,130; "Steroid Receptor Modulator Compounds and Methods", T. K. Jones, M. E. Goldman, C. L. F. Pooley, D. T. Winn, J. P. Edwards, S. J. West, C. M. Tegley, L. Zhi, L. G. Hamann, L. J. Farmer, R. L. Davis, U.S. Pat. No. 5,696,133.}
The conversion of 5 to 7 utilizing a Skraup reaction limits the variety of compounds that can be prepared by this route due to the need to use a ketone (6) as one of the reaction partners; the substituents on C(2)-C(4) cannot be varied independently. The present invention addresses this limiting aspect of the Skraup reaction.